MegaSquirt (MS3) or Holley HP EFI

Personal opinion, hard to beat an 8HP70 or similar for a drag and drive event. As mentioned, built in transbrake, plus wicked fast shifts and more steps from first to 1:1 (6th) to keep the motor in the power band. Plus, after all is said and done, throw it in drive and cruise at 1500 rpm or something low like that. Might even be able to program a "sport mode" button for drag race snap your neck shifts and then tone it down when cruising to the next venue. Additionally, because first is 4.70ish, the rear gear can be something much milder and maybe cheaper because most people with a 2.94 throw/give it away.